Continuous motion packaging machines, including those machines which package articles such as beverage containers or food containers, are well known. These continuous motion packaging machines typically group a selected number of articles into a desired configuration, for example a six pack configuration, then package the articles into a carton or carder formed from a paperboard blank. When packaging bottled or canned beverages, for example, the articles are grouped and either moved singularly or as a group into an open, preassembled carton, at which point the carton is sealed. In another configuration, a wrap-around paperboard carton blank is folded or wrapped around the preconfigured article group, and then sealed so that the packaged articles are ready for shipment.
Whichever type of carton is used, the packaging of the article group into the paperboard carton blank occurs while the article or articles are passed from an infeed area along a path of travel through a packaging machine, and to an outfeed area. This allows the articles to be packaged in a continuous operation, which normally carries on without interruption.
Many types of paperboard carders, including the wrap-around type, are manufactured of paperboard carton blanks which include fold lines, score lines, and preformed flaps. These flaps act as article stabilizers or reinforcing members for the articles enclosed within the paperboard blank as it is formed into a carton or carrier. The reinforcing flaps serve to restrict article movement and to prevent contact of adjacent articles once the carrier has been wrapped around the article group and tightened or locked, which is usually accomplished by placing a tab formed on one portion of the paperboard blank into an aperture formed in an adjacent bottom panel. A typical reinforcing flap, therefore, would merely be a portion of the side panel of the paperboard carrier defined by partial cuts or score lines.
Thus, when paperboard carton blanks are used for packaging articles the reinforcing flap is a part of, and is aligned with, the sidewall of the carton blank. As the paperboard carrier or carton blank is wrapped around a bottle group, however, the reinforcing flap is not automatically biased into its final position in which it will project inwardly from the sidewall and into the bottle group. The flap must be moved into the appropriate orientation by a separate mechanism.
An advantage of packaging articles into paperboard carriers is to utilize the carrier for advertising and/or promotional purposes, so that it forms a display or advertisement. Thus, it is important that when forming the carton blank around the articles of product, that the paperboard carrier not be torn or damaged. If the paperboard carrier becomes torn or damaged, not only will the package fail to secure the articles in position within the carrier, the carrier will also lose its aesthetic appeal. Thus, it is of paramount concern that not only is the paperboard carrier properly formed around the articles, it is also important that this be accomplished in a manner which does not damage the paperboard carrier and/or the advertising carried thereon.
A number of flap folding mechanisms have been developed for use in packaging machines to bend or fold the reinforcing flaps of the paperboard carrier into the proper orientation. The step of folding or bending the reinforcing flaps usually occurs just prior to the tightening and closure of the paperboard carrier around the bottle group. In many of these operations, the packaging mechanism must engage a specific area of the carton blank in a particular manner in order to accomplish the desired step of folding the flaps of the carrier inwardly for locking the bottles into position. It also must be kept in mind that this operation is performed while the carton blank is in a continuous motion path of travel, often at a high speed, through a packaging machine. Thus, the folding mechanism must be specifically designed to operate in timed relationship with the moving carton blanks. In addition, such wrap-around cartons may include several flaps, perhaps as many as two or three flaps per side, all of which must be folded to reinforce and separate adjacent articles of product within the carton blank.
In the past, the task of folding the reinforcing flaps of carton blanks was done by flap folding mechanisms which included numerous mechanical engaging devices that were sequentially aligned with the prescored flap areas of the carton blank sidewall and moved into the carton blank to fold the flaps to a first position. The folding mechanism then mechanically folded the flaps even further, so that the flaps would not spring back into a position in which they would become closed on the carton blank sidewall when engaging the articles within the carton blank. A problem associated with these flap folding devices, however, was that the activation of the engagement device to fold the flaps to the furthest extent within the carton blank often resulted in the shifting of the entire carton blank in the direction of the path of travel, which would result in the misalignment of the carton blank within the other flap folding devices.
Since the transverse alignment of a moving carton blank with the engagement mechanism of a flap folding device is important, carton blank shifting can have a significant effect on the entire packaging operation. If a carton blank is shifted sufficiently, subsequent engagement mechanisms will not appropriately align with the prescored flap areas, and the remaining and sequentially positioned engagement mechanisms will impact the carton blank sidewall at a position other than that where a prescored flap area is defined, resulting in the bending or tearing of the carton blank. When this occurs in a high speed packaging operation, the entire process flow is interrupted, which not only causes the packaging machine to shut down, but shuts down the entire packaging line also.
Moreover, with the development of packaging machines capable of processing articles of different sizes, diameters, and article group configurations, attention has been focused on the development of modular article engagement mechanisms, to include reinforcing flap folding devices. This has been done in order to allow for quicker changeover of the folding device needed for particular carton designs. Prior to the development of modular folding devices, article engagement devices were typically carried on or in a continuous chain or belt moving in timed relationship with the group of articles along the path of travel. Such an arrangement, however, does not provide the flexibility needed in modem packaging operations, and is not readily adapted for use with contemporary and multi-configurable packaging machinery.
One example of a prior art machine is disclosed in U.S. Pat. No. 4,563,8532 Calvert. The device of Calvert is mounted on an endless chain conveyor which is driven along the carton blank's path of travel and is aligned, and moved in timed relation, with specific areas of the carton blank. One problem with this type of arrangement, however, lies in the fact that this type of system is not readily interchangeable or adjustable to accommodate various carton blank sizes or shapes which can be processed on modern multi-configurable packaging machines. Changing over to engage different types or sizes of cartons will require the disassembly and reassembly of the entire conveyor system, or the inclusion of a chain phasing mechanism, not taught in Calvert. Calvert accomplishes the folding of the flaps by introducing a stud into the prescored flap area, on which a pair of flap folding elements are pivotally mounted and moved to engage the reinforcing flaps for folding the flaps inwardly in relation to the bottles in the group of bottles being packaged.
A similar approach is disclosed in U.S. Pat. No.4,970,843 to Louret et al. The mechanism of Louret et al is carried by a chain conveyor, and is adapted to sequentially engage the prescored flap areas of a carton blank, and to sequentially fold the carton flaps through the movement of a pair of pivotal folding arms which will open the flaps inwardly of the carton blank.
An example of a modular carton engaging mechanism is shown in U.S. Pat. No. 4,612,753 to Taylor et al. The device of Taylor includes one or more fingers which are urged into contact with locking tabs on the paperboard carrier to force the locking tabs through an opening on the carrier. The fingers may be actuated either by a rotating cam operating device, or may be electromagnetically actuated. These locking fingers are carried on a rotating wheel located in a stationary position along the path of travel of the packaging machine. Unlike the patents to Calvert and Louret et al, discussed above, however, the device of Taylor et al, includes a mechanically operable mechanism which must first be inserted into the prescored flap area of a carton blank, and then actuated to effect a folding of the flaps thereof.
A device similar to Taylor et al, is disclosed in PCT patent application No. PCT/US94/10787. The PCT application discloses a flap folding mechanism incorporated on a rotating wheel fixed in position with respect to a carton blank moved along the packaging line. The device of the PCT application discloses a folder having pivotal fingers for engaging and folding pairs of flaps formed in the carton blank sidewall and moved into the carton blank, whereupon the pivotal fingers are moved to open the flaps to a further extent.
While the modular carton engaging or flap folding mechanisms of Taylor et al, and the PCT application may appear to be more versatile than the prior art chain conveyor assemblies, all of the known flap folding devices, whether modular or driven along a chain conveyor, are adapted to sequentially engage adjacent prescored flap areas define in the sidewall of a carton blank, and to sequentially fold the flaps inwardly through a two step process in which a finger is first inserted into the carton blank sidewall, and then the finger is actuated to open the flaps to a further extent.
Thus, the known flap folding devices involve the steps of mechanically opening the flaps defined in a carton blank sidewall inwardly to a first extent, and then to a second extent. Moreover, the prior art devices all use moving probes or studs having mechanically actuated fingers which are inserted into the opening, opened, and retracted, whereupon the stud or probe is withdrawn from the prescored flap area.